list_accounts

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are supplied, so the description must carry the full behavioral burden; it usefully discloses the empty-return case and that the return value contains further guidance. It does not state that the call is read-only with no side effects, nor whether it requires any local or auth setup, so an agent cannot fully characterize the behavior from the description alone.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, with no wasted words: first what the tool lists and its fields, then the edge-case behavior. The core purpose is front-loaded and the caveat follows it.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, the description need not explain return values, and it correctly focuses on the one edge case (empty result means uninitialized). For a zero-param discovery tool, this is nearly complete; only the absence of read-only and side-effect reassurance keeps it from a 5.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is no parameter semantics to obscure; the baseline 4 applies. The mention of returned fields is a bonus that helps interpret the result, though the output schema already covers that.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb and resource ('列出已配置的邮件账户') and names the fields returned (id, 登录用户, IMAP 服务器), so the agent knows exactly what this tool surfaces. It doesn't explicitly distinguish itself from the sibling email tools, but those all operate on folders or messages, so there is no real ambiguity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

For an agent looking for configured accounts, usage is implied, and the note about empty results and initialization provides some practical guidance. However, it never states when to call this tool versus the sibling tools, for example, that it is a discovery step before list_folders or search_emails, and it does not state prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.